Many advances have been made in recent years in the fitting of contact lenses. Nonetheless most contact lens wearers begin to feel some discomfort when wearing these contact lenses after a short period of time. In addition because of the hydrophobic nature of the lens the natural tear film of the eye is not able to properly coat the lenses leading to reduced visual accuity, irritation and with the prolonged use of contact lenses edema of the corneal epithelium.
In order to reduce irritation, insure comfort and increase visual accuity when wearing contact lenses, various wetting solutions have been suggested. These solutions have been applied to the contact lens before insertion into the eye and have also been applied to the eye. These wetting solutions have primarily involved the use of polyvinylalcohol as wetting agents and various cellulose derivatives as viscosity building agents. A recent U.S. Pat. No. 3,549,747 describes an aqueous wetting solution containing polymeric viscosity building agents. Although these solutions tend to eliminate the conditions described hereinabove, like all previous wetting solutions the effect of these solutions is short lived.
Solid polymeric water soluble inserts placed in the eye of a patient wearing contact lenses acts as a wetting agent and is effective in improving clarity of vision, improve lens wearing comfort and wearing time over a much longer period of time than heretofore possible with wetting solutions.
This polymer insert, therefore when inserted in the cul-de-sac of the eye present concurrently while wearing the contact lens slowly dissolves, affording a continuous long term release of artificial tears and thereby maintaining the wetness of the lens while in the eye, providing better tear circulation and resulting in improved and more efficient metabolic exchange.
It has been surprisingly found that a non-toxic water soluble solid polymer inserted into the cul-de-sac of the eye is effective in relieving the symptoms mentioned herein. It was not expected that such a polymer, which in the past had been used merely as a viscosity agent, could in a solid form act by itself to relieve such symptoms. It has also been surprising to find that such a water soluble polymer in solid form while uniformly dissolving in the eye would provide the necessary wettability of the contact lens for a period of at least several hours.